From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ankur Arora <ankur.a.arora@oracle.com>,
linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org,
luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com,
hpa@zytor.com, mingo@redhat.com, juri.lelli@redhat.com,
vincent.guittot@linaro.org, willy@infradead.org, mgorman@suse.de,
jon.grimm@amd.com, bharata@amd.com, raghavendra.kt@amd.com,
boris.ostrovsky@oracle.com, konrad.wilk@oracle.com,
jgross@suse.com, andrew.cooper3@citrix.com,
Joel Fernandes <joel@joelfernandes.org>,
Youssef Esmat <youssefesmat@chromium.org>,
Vineeth Pillai <vineethrp@google.com>,
Suleiman Souhlal <suleiman@google.com>,
Ingo Molnar <mingo@kernel.org>,
Daniel Bristot de Oliveira <bristot@kernel.org>
Subject: Re: [POC][RFC][PATCH v2] sched: Extended Scheduler Time Slice
Date: Mon, 30 Oct 2023 08:56:50 -0400 [thread overview]
Message-ID: <ce0dbdaf-6be4-4f3b-9b5a-aedeac00ddf6@efficios.com> (raw)
In-Reply-To: <20231027124930.3753cdd4@gandalf.local.home>
On 2023-10-27 12:49, Steven Rostedt wrote:
> On Fri, 27 Oct 2023 12:35:56 -0400
> Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:
>
>>> Does that make more sense?
>>
>> Not really.
>>
>> Please see my other email about the need for a reference count here, for
>> nested locks use-cases.
>
> Note, my original implementation of nested locking was done completely in
> user space.
>
> int __thread lock_cnt;
>
> extend() {
> if (lock_cnt++)
> return;
> ...
> }
>
> unextend() {
> if (--lock_cnt)
> return;
> ...
> }
This only works if "your" lock implementation is the only user of this
RSEQ feature within a process. RSEQ requires that multiple libraries can
share the facilities. Therefore, the rseq field should include the
nesting counter as part of the RSEQ ABI so various userspace libraries
can use it collaboratively.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
next prev parent reply other threads:[~2023-10-30 12:56 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-26 3:54 Steven Rostedt
2023-10-26 10:59 ` Peter Zijlstra
2023-10-26 11:14 ` Steven Rostedt
2023-10-26 18:36 ` Mathieu Desnoyers
2023-10-26 18:50 ` Linus Torvalds
2023-10-26 18:59 ` Mathieu Desnoyers
2023-10-26 19:36 ` Steven Rostedt
2023-10-26 20:45 ` Steven Rostedt
[not found] ` <644da047-2f7a-4d55-a339-f2dc28d2c852@efficios.com>
[not found] ` <20231027122442.5c76dd62@gandalf.local.home>
2023-10-27 16:35 ` Mathieu Desnoyers
2023-10-27 16:49 ` Steven Rostedt
2023-10-30 12:56 ` Mathieu Desnoyers [this message]
2023-10-30 13:45 ` Steven Rostedt
2023-10-30 18:05 ` Mathieu Desnoyers
2023-10-30 18:19 ` Steven Rostedt
2023-10-30 18:27 ` Mathieu Desnoyers
2023-10-30 18:39 ` Steven Rostedt
2023-10-26 19:20 ` Steven Rostedt
2023-10-26 21:35 ` Steven Rostedt
2023-10-27 21:52 ` Steven Rostedt
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